The examination of 250 cases of onchocerciasis from the Sudan-savanna of northern Cameroon showed a strong association between microfilarial invasion of the eye and microfilarial skin concentrations at the outer canthus. It was also shown that the presence of a head nodule was associated with a high microfilarial skin concentration around the eye. It is suggested that these findings are of practical importance in the field for the early detection of cases at risk of developing serious ocular lesions.